Some chromium (VI) compounds are documented human propose measuring the intracellular oxidation state of Cr carcinogens, but the exact mechanism of Cr induced cancer is unknown. Oxidation state determination of intracellular Cr will provide important information relevant to exposure and risk assessment, and for understanding the mechanism of Cr carcinogenesis. We propose measuring the intracellular oxidation state of Cr using x-ray absorption near edge structure (XANES) spectroscopy. Until now, the XANES technique was not very practical, relying on costly synchrotrons. This valuable technique could be implemented using a lower power cost-effective system incorporating a revolutionary toroidal crystal optic. XOS has successfully carried out the Phase I research and demonstrated the feasibility of Cr oxidation determination using a table-top XANES system operated with samples in air. In this Phase II project, a fully optimized system will be designed. Human cells will be prepared in culture mediums and treated with Cr exposure. The reduction of Cr(Vl) to Cr(lll) will be monitored using the XANES system. The practical application of this XANES technique for clinical research and its commercialization will be evaluated. This would make available, for the first time, a broad chemical-state measurement capability covering most of the periodic table in a compact, low-power table-top system for medical, research, and industrial applications.